This invention relates to a single-handle faucet of the type which can control both the flow rate and the mixing ratio of two different fluids, such as hot and cold water, using only a single handle. More particularly, it relates to a single-handle faucet which is economical to operate.
Single-handle faucets such as water faucets for sinks, bath tubs and showers have become extremely popular because they allow the user of the faucet to control both the flow rate and the temperature of the water discharged from the faucet using one hand. However, it has been found that such faucets are wasteful with respect to water consumption. One reason for this is that the handle of a single-handle faucet is very easy to manipulate, so users have a tendency to move the handle to a position corresponding to maximum flow rate from the faucet. In some faucets, the action of the handle is stiffened in order to make it more difficult for the user to move the handle to its maximum position so as to reduce water consumption. However, the user then tends to exert a large force on the handle to overcome the stiffness, or else the user grasps the handle at its extreme outer end to increase the lever arm, with the result that the handle is again moved to its maximum position, resulting in excessive consumption of water.
In addition, children and other persons having poor motor control sometimes have difficulty adjusting a conventional single-handle faucet to an intermediate position between fully open and fully closed, so they tend to open the faucet more than is necessary. Furthermore, even children who are sufficiently coordinated to operate such a faucet often lack an appreciation of the cost of water, and they move the handle to a position of maximum flow rate.
U.S. Pat. No. 4,708,172 discloses a faucet equipped with a device for restricting the flow of a water through the faucet to an intermediate level which is less than the maximum flow rate. The user can increase the outflow of water from the faucet beyond this intermediate level by raising the handle of the faucet against the action of a resilient tongue. However, that device has the disadvantage that the force required to operate the faucet is increased by the resilient tongue, making flow control difficult and requiring the user to exert a force which may be too great for a child or infirm person. In addition, the flow of water returns to the intermediate level as soon as the user releases the handle, so in order to obtain a continuous, high flow rate, the user must continuously press the handle against the force of the resilient tongue. This operation is not only tiring but occupies one hand of the user, making it impossible for him to wash his hands, for example. Furthermore, when the handle is moved beyond the intermediate level, it is not possible to adjust the mixing ratio of hot and cold water.